Forgive me- I get the same result and the x wing on 9 as quoted but can't find the 15 to make up a 159 xy wing. There is a kind of x wing 579 with pivot at r5c5 that leads to a 5 at r4c4 but for me no obvious continuation
HELP

Forgive me- I get the same result and the x wing on 9 as quoted but can't find the 15 to make up a 159 xy wing. There is a kind of x wing 579 with pivot at r5c5 that leads to a 5 at r4c4 but for me no obvious continuation
HELP

The X-Wing takes out a 9 from r8c2, which then becomes the XY-Wing pivot.

I am hardly an expert on such things, but that might be an XY-Wing with r5c13 being a pseudo cell, i.e., the two cells act as one 57 pincer. Then you would treat it as an XY-Wing=>r4c13<>5 rather than having to look at each value of r5c5.

If by any chance Keith sees this, he'll be able to give the final word.